Not to mention Growlithe, as far as I recall (but it's been a long time) isn't caught anywhere near the "early game" of RGB/FRLG either, and is replaced by Vulpix in both RGB/FRLG and GS/HGSS, where it IS relatively early game. Shinx is also feline in both the Japanese (where it's called as a tiger) and the English (where it's a lion) versions, but that's not really that big of a differentiation for Gamefreak.
The only other "early game" archetype I can really noticed is an "early Electric-type". And Electrike really isn't super early.
Yeah the only clear arch-types we've really had time and time again are:
- The early bird Pokemon (Pidgey, Hoothoot, Tailow, Starly)
- The other bird Pokemon (Spearow, Natu, Wingull, [Gen4 doesn't really have one])
- Early rodent Pokemon (Ratata, Sentret, Zigzagoon, Bidoof)
- Early sucky bug types (Caterpie+Wurmple, Spinarak+Ledyba, Wurmple[Counts as 2 because of it's multiply evolutions], Kricketot [Lacks a "partner" because of Burmy and Combee])
There is also a few others but they aren't as clear-cut (IMO) as the ones above (The fish you caught with a great rod, The normal-type cat [replaced by Snubbull in gen2 >_>]).
tl;dr : yeah we could sit here all day and try to find a pattern in Pokemon, but there really isn't outside of the early bird/rodent/bug. Which could be said is a good thing, because it would be lame to just have extremely exact roles fulfilled each generation, would make the designs a bit too cookie-cutter.